Method of manufacturing alkylene oxide adducts of an aliphatic alcohol

ABSTRACT

An improvement is provided in the manufacture of alkylene oxide adducts of an aliphatic alcohol in which the reaction mixture, comprising the alkylene oxide adduct, unreacted alcohol, acid catalyst residue, carbonyl compounds and hydrocarbons, is treated to remove unreacted alcohol for recycle to the adduct formation step. To prevent the build-up in the system of carbonyl compounds and hydrocarbons which are not easily distillable from the recycle alcohol because of their respective boiling points, at least a portion of the recycle alcohol is esterified with boric acid, the esterification mixture is subjected to distillation to remove volatile portions, and the borate ester thus obtained is hydrolyzed to recover the alcohol which is recycled to the adduct formation step.

This is a division of application Ser. No. 271,685 filed July 14, 1972.

BACKGROUND OF THE INVENTION

This invention relates to an improved method of manufacturing alkyleneoxide adducts of an aliphatic alcohol, said alcohol having been obtainedby the liquid phase oxidation of a saturated aliphalic hydrocarbonhaving 8 to 20 carbon atoms in the presence of a boron compound bycontacting with a molecular oxygen containing gas.

In the addition reaction of alkylene oxides to alcohols in the presenceof an acid catalyst, it is known that the conversion of alcohols must beto an extent of 30 to 80 % from the economic point of view, so that itis necessary to recover unreacted alcohols by means of, e.g.,distillation, and to recycle the recovered alcohols to the reactionsystem.

Not only alcohols obtained by the oxidation of hydrocarbons but alcoholsin general may contain impurities, e.g. carbonyl compounds andhydrocarbons, which do not react with alkylene oxide. Such impuritiesare accumulated in the system with the recycle of recovered alcohols andthis makes it difficult to obtain a product of a uniform quality bycontinuing the reaction under the same conditions. As the reaction iscontinued or repeated, the content of the impurities gradually increasesand, with this, the average number of moles of added alkylene oxide (itwill hereinafter be referred to as n.) per mole of alcohol in theproduct gradually varies. Therefore, it is necessary in order to obtaina product of a uniform quality to continually adjust the feed rate offresh alcohol and/or alkylene oxide and to vary the material balance inthe separation step of unreacted alcohol and of impurities by means of,e.g., distillation. Unfortunately, it is difficult to completelyseparate the impurities, because of the relationship of their boilingpoints to that of the alcohol and the accumulated impurities at lastmake it impractical to recycle the recovered alcohol.

If the impurities contained in raw alcohols are simple carbonylcompounds or olefinic compounds hydrotreating may be employed in thepurification step. Such a treatment has been utilyzed in practical toimprove color and odor of the products but is ineffective for thecomplete removal of impurities contained in raw alcohols, e.g.hydrocarbons.

Therefore, there is a need for an improved method of manufacturingalkylene oxide adducts of aliphatic alcohols having uniform good qualityin which removal of accumulated impurities is attained economically andefficiently.

An object of the present invention is to provide an improved method ofmanufacturing alkylene oxide adducts of aliphatic alcohols havinguniform good quality in which removal of accumulated impurities isattained economically and effectively.

SUMMARY OF THE INVENTION

An improvement is provided in the manufacture of alkylene oxide adductsof an aliphatic alcohol in which a saturated aliphatic alcohol having 8to 20 carbon atoms is subjected to the reaction with an alkylene oxidehaving 2 to 4 carbon atoms in the presence of an acid catalyst andunreacted alcohol containing impurities comprising hydrocarbons andcarbonyl compounds are separated from the reaction mixture. Theimprovement comprises;

a. subjecting at least a portion of said unreacted alcohol toesterification with a boric acid to form a borate ester of said alcohol,

b. removing said impurities from the esterification mixture,

c. subjecting the borate ester thus obtained to hydrolysis to recoverthe alcohol and

d. recycling the recovered alcohol to the adduct formation step.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, alkylene oxide adducts ofaliphatic alcohols having uniform good quality are produced from analiphatic alcohol having from 8 to 20 carbon atoms per molecule andcontaining impurities which do not react with alkylene oxide. Saidadducts are obtained by (1) subjecting said alcohol to reaction withpre-determined amount of an alkylene oxide in the presence of acidcatalyst (this step will hereinafter be referred to, for short, as"alkoxylation".), (2) recovering unreacted alcohol by means of, e.g.,distillation, from the reaction mixture, if necessary after removal ofthe catalyst and some by-products, formed in the alkoxylation, (3)reacting a portion or all of the recovered alcohol with a boric acid,(4) separating the resulting boric acid ester from the impurities, (5)hydrolyzing the separated borate ester to liberate the alcohol, and (6)recycling the alcohol thus obtained to the alkoxylation step, ifnecessary after removal of moisture, in combination with the otherportion of the recovered alcohol which is not subjected to theesterification reaction.

In the above process, the concentration of impurities in the recycledalcohol increases with continuation of the operation to a certain valuebut thereafter becomes constant. Therefore the impurities contained inthe raw material do not cause such troubles as mentioned above inconnection with the prior art and, consequently, there is obtained aproduct of uniform good quality economically and continuously, becausethe alkoxylation reaction and the recovering unreacted alcohol can beconducted uniformly.

In addition, in accordance with the present invention, it is possible toproduce commercially and continuously alkylene oxide adducts of alcoholshaving uniform good quality by using the above process in combinationwith the oxidation process of saturated aliphatic hydrocarbons toalcohols. To say, the method of the present invention makes it possibleto produce directly alkylene oxide adducts of saturated aliphaticalcohols directly advantageously from aliphatic hydrocarbons without anyparticular unit process, effectively utilizing the impurities containedin said alcohols, which have hithereto been discarded.

The present invention will be understood best in connection with theaccompanying drawings wherein;

FIG. 1 is a flow diagram illustrating the fundamental of the method ofmanufacturing alkylene oxide adducts of aliphatic alcohols in accordancewith the present invention,

FIG. 2 is a flow diagram illustrating an embodiment of the process ofthe present invention in combination with the manufacture of thealcohol, and

FIG. 3 is a flow diagram illustrating another embodiment of the processof the present invention in combination with the manufacture of thealcohol.

Illustrating the present invention with respect to FIG. 1, inalkoxylation step there are added to the alcohol an acid catalyst and analkylene oxide. The starting alcohol can be any saturated aliphaticalcohol having 8 to 20 carbon atoms per molecule. In general, alcoholsobtained by liquid phase oxidation of straight chain saturated aliphatichydrocarbons having 8 to 20 carbon atoms per molecule by molecularoxygen containing gas in the presence of a boron compounds areconveniently used as such. As the alkylene oxide there are used thosecontaining 2 to 4 carbon atoms per molecule, the preferred ones beingethylene oxide and propylene oxide. Mixtures of two or more of suchalkylene oxides can also be used. As the acid catalyst there can be usedmineral acids such as sulfuric acid and phsphoric acid, or Lewis acidsor Friedel-Crafts catalysts. Among such acid catalysts, the mostsuitable are boron trifluoride and its complexes with, e.g., methanol,ethanol, isopropanol, butanols, ethylether, n-butylether, phenylether,acetic acid, propionic acid, phenol, monomethylamine, monoethylamine,dimethylamine, triethylamine or piperidine, tin chlorides and antimonychlorides.

The mole ratio of alcohol to alkylene oxide fed to the reaction zone foralkoxylation, although it varies in accordance with the n of the endproduct, is 0.5 to 4, preferably 0.8 to 2.0 since the n is usuallyrestricted to 1 to 6 by the nature of the acid catalysted alkoxylation.The acid catalyst is usually used in an amount of 0.01 to 1 %,preferably 0.05 to 0.5 % by weight based on the weight of the alcohol.

The reaction may be conducted in either a batchwise operation or acontinuous operation. In the case of a batchwise operation, it isconvenient to charge first the alcohol and the catalyst to a stirredreaction vessel and then add slowly thereto the alkylene oxide.

In case of the continuous operation, it is convenient to pass thecatalyst containing-alcohol through a tubular reactor while addingthereto the alkylene oxide from two or more inlets positioned in thewall of the tubular reactor. The temperature, pressure, reaction timeand other conditions can be properly selected depending on the kind andamounts of raw alcohol, alkylene oxide and catalyst used. Usually, thereaction temperature will be properly selected from the range betweenroom temperature (20°C) and 100°C.

After the alkoxylation, if desired, the catalyst and by-products areremoved from the reaction mixture. The catalyst can be removed byneutralization and subsequent filteration of the reaction mixture or byextraction with water. Among the by-products of alkoxylation,water-soluble polyalkylene glycols and dioxanes can be removed byextraction with water.

Distillation is the most convenient means for the recovery of unreactedalcohol; the alkylene oxide-alcohol adduct being recovered as theresidue. The recovered alcohol is in whole or in part subjected toesterification with a boric acid. Althought the larger the proportion ofrecovered alcohols subjected to the esterification, the higher thequality of the end product, it is preferred to subject 1 to 50 % ofrecovered alcohol to the esterification from a commercial point of view.In the case where unreacted alcohols is recovered by distillation, theobjects of the present invention are attainable more efficiently bysubjecting to esterification a forerun amounting to 1 to 20 % of theentire distillate to the esterification. In Example II hereinafter setforth the recovered alcohol was processed in this manner, and theadvantage is apparent from the comparison of the result in Example IIwith that of Example I and of Comparative Example I.

The boric acids used in the esterification include orthoboric acid,metaboric acid, pyroboric acid and boric acid anhydride, although ispreferably used orthoboric acid. The boric acid can be used in anamount, such as to provide 0.3 to 3, preferably 0.4 to 1.5 gram-atoms ofboron atom per mole of alcohol.

The esterification usually is carried out using a stirred reactionvessel at temperatures of 100° to 200°C under a reduced pressure or inan atmosphere of an inert gas such as gaseous nitrogen with immediateremoval of liberated water when water is liberated as a result ofesterification. Usually a reaction time of 10 to 100 minutes issufficient.

Separation of impurities from the esterification product is convenientlyattained by an ordinary distillation. The impurities are removed asdistillate and the boric acid ester of the alcohol is recovered asresidue. The distillation preferably is conducted under reduced pressureto minimize thermal decomposition of the product and a still betterresult is obtained by use of a thin film evaporator because of a shorterresidence time. The distillation may be conducted in the presence of aninert solvent of a lower boiling point than the impurities in order toaid effluence of the impurities. The distillate contains impuritieswhich originate from the raw alcohol and remain unreacted duringalkoxylation, such impurities generally comprising hydrocarbons andcarbonyl compounds. Although the impurities are in most cases discarded,there are good uses therefor as illustrated hereinafter in connectionwith FIG. 2 and FIG. 3.

The boric acid esters thus obtained as residue in the distillationkettle is then hydrolysed. The hydrolysis may be carried out in variousways, e.g. in a batch operation using a stirred tank, or in a continuousoperation or by means of a counter-current extractor. Water preferablyis used in a weight ratio to the residue of 10:1 to 1:10. Thetemperature can be varied within the range from room temperature (20°C)to 200°C. Sometime, it is advantageous to carry out the hydrolysis attemperatures above 100°C under pressure.

The alcohol yielded in the hydrolysis is separated as an oily layer fromthe aqueous boric acid solution. From the squeous boric acid solution isrecovered boric acid which is then recycled to the esterification stepwhile the mother liquor from the recovery of boric acid is recycled tothe hydrolysis step.

The alcohol thus obtained is combined with the remainder of recoveredalcohols which has not been subjected to esterification and, afterremoval of moisture if required, recycled to the alkoxylation step.

As mentioned above, in the method of the present invention, impuritiesof the same or similar boiling points as those of the recovered alcoholare substantially completely eliminated as a low boiling fraction duringthe distillation, because the unreacted alcohol fraction separated fromthe alkoxylation mixture after completion of the reaction is, in wholeor in part, subjected to esterification with a boric acid and then todistillation to separate the recovered alcohol as residue in the form ofa boric acid ester. Thus, impurities can be eliminated to the extentdesired during purification of the recovered alcohol, so that the purityof the alcohol recycled to the alkoxylation stage becomes constant.

This makes it possible to continuously produce alkylene oxide adducts ofaliphatic alcohols having uniform good quality without any adjustment ofreaction conditions for the alkoxylation and conditions for recovery ofunreacted alcohol. Example I and Comparative Example I are provided forthe purpose of the simplest comparison of the method of the presentinvention with a conventional method. The superiority of the method ofthe present invention will be easily understood by the comparison.

It is more advantageous to combine the method of the present inventionwith the preparation of aliphatic alcohols by liquid phase oxidationwith a molecular oxygen containing gas of corresponding straight chainsaturated aliphatic hydrocarbons having 8 to 20 carbon atoms permolecule in the presence of a boron compound. Any aliphatic hydrocarbonhaving 8 to 20 carbon atoms can be subjected to oxidation, thoughconveniently used are n-octane, n-nonane, n-decane, n-undecane,n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane,n-heptadecane and n-octadecane. Mixtures of two or more of suchhydrocarbons having 10 to 16 carbon atoms are suitably used incommercial operation.

As the boron compound there may be used, other than boric acids, any ofboron compounds which will yield boric acids upon contact with water.Preferred compounds are orthoboric acid, metaboric acid, boricanhydride, salts thereof, borate esters and boroxines.

The flow diagrams of FIG. 2 and FIG. 3 illustrate such combinations.Illustrating in more detail with reference to FIG. 2, in oxidation stage(a), an aliphatic hydrocarbon is oxidized in liquid state in thepresence of 1 to 5 % by weight, caluculated as metaboric acid, based onthe weight of the hydrocarbon of a boron compound with a molecularoxygen containing gas containing 2 to 21 % by volume of molecular oxygenin an inert gas such as gaseous nitrogen, at temperatures of 140° to200°C, preferably 150° to 190°C. The conversion of the hydrocarbons isusually restricted to at most 30 %, preferably 10 % to 20 %, in order toobtain the alcohol in a high yield. The reaction time can range from 0.5to 4 hours, preferably from 1 to 3 hours. In esterification step (b),the oxidation mixture is maintained usually at a temperature of 100° to200°C, preferably at a temperature in the neighbourhood of the oxidationtemperature under reduced pressure or in an atmosphere of an inert gasfor 10 to 100 minutes. The esterification step is employed forconversion of a portion of the recovered alcohol recycled from thealkoxylation stage in addition to completion of esterification of theoxidation product. When the boron compound is present insufficiently inthe system, it may be added in the stage to the system. In the followingdistillation step (c), unreacted hydrocarbon is distilled off togetherwith volatile by-products. The distillation preferably is carried out ata temperature as low as possible and, accordingly, under reducedpressure. It is favorable to carry out the distillation in two stages toshorten the residence time of the effluent and to conduct the secondstage in a thin film evaporator. The distillate is recycled to theoxidation step, preferably after the purity of hydrocarbons in thedistillate has been increased by saponification or hydrotreating (d).

Hydrolysis (e) of the boric acid ester of the alcohol obtained asresidue is performed in a similar manner as in the description of theprocess illustrated in FIG. 1. In separation step (f), boric acid isrecovered from the aqueous solution separated to the preceedinghydrolysis step (e) by crystallization and, after dehydration ifrequired, recycled to the oxidation step, while the mother liquor may berecycled to the hydrolysis step for economization of the process.

The crude alcohol separated as an oily layer in the hydrolysis step isthen purified (g) in various ways. For instance, it is purified usuallyby means of distillation following such post treatments as, e.g.,saponification by contact with an alkali hydroxide, such as potassiumhydroxide or sodium hydroxide, washing with water, hydrotreating bycontact with hydrogen in the presence of a metallic catalyst. Thepurification method consisting of the steps of saponification, washingwith water and distillation, combined in this order, as indicated inFIG. 2 is just by way of example and, of course, this purificating maybe carried out using other variations.

Alkoxylation step (h), catalyst removal (i) and distillation (j) arecarried out in the same ways as explained in connection with FIG. 1.

The recovered alcohols obtained in the distillation of the product ofstep (j) may be recycled (k) in whole or in part to either oxidationstep (a), esterification step (b) or distillation step (c), though it isparticularly desirable for avoidance of undesirable side reactions ofthe recovered alcohol and completion of esterification to recycle it toesterification step (b). In the case of a process in which theesterification step (b) is omitted, the alcohol may be recycled to theoxidation step (e) or distillation step (c). The balance of recoveredalcohol unrecycled to the oxidation step (a), (a), esterification step(b) or distillation step (c) is recycled, if necessary after dehydrationor drying (1), to the alkoxylation step. A better result is obtainableby recycling the forerun from the distillation (j) to the esterificationstep (b) and the other fractions to the alkoxylation step (h).

In accordance with the process as shown in FIG. 2, there is continuouslyproduced from a hydrocarbon as mentioned above an alkylene oxide adductof a corresponding alcohol having uniform good quality in a high yeildwithout careful adjustment of conditions for alkoxylation anddistillation. This process will be illustrated specifically in ExampleIII.

The process as shown in FIG. 3 is a modification of the process as shownin FIG. 2. After liquid phase oxidation (a) of a hydrocarbon in thepresence of a boron compound in a similar manner as explained inconnection with in FIG. 2, the reaction mixture is directly subjected tohydrolysis. The hydrolysis (b) may be carried out in various ways in thesame manner as the hydrolysis (e) in the process of FIG. 2. The aqueousboric acid solution thus formed is separated (c) and from the solutionis recovered boric acid by crystallization which in turn is recycledafter dehydration if required to the oxidation step, while the motherliquor is recycled to the hydrolysis step (b). The organic layerobtained is saponified by contact with an alkali hydroxide, such aspotassium hydroxide, sodium hydroxide or lithium hydroxide, and washedwith water (d). The saponification preferably is conducted attemperatures of 100° to 200°C for few minutes to several hours using anaqueous alkali hydroxide solution of a concentration of 1 to 50 % byweight.

The esterification in esterification step (e) is carried out under thesame conditions as explained in connection with the esterification inthe process of FIG. 1. In distillation step (f), unreacted hydrocarbonis separated in a similar way as in the distillation step (c) in FIG. 2,and the distillate (g) is recycled to the oxidation step (a). Hydrolysisstep (h) and separation (i) correspond to the hydrolysis step (e) andseparation (f) in FIG. 2 are conducted in a similar manner. Recovery andrecycle of boric acid and recycle of the mother liquor from the recoveryof boric acid are also carried out in a similar manner.

Purification (j) of crude alcohol is performed by means of distillationas in the process of FIG. 2, and alkoxylation (k), catalyst removal (1)and distillation (m) correspond alkoxylation (h), catalyst removal (i)and distillation (j) in the process of FIG. 2, respectively. A portionor the whole of the recovered alcohol obtained by distillation isrecycled (n) to either one of the steps of oxidation (a), hydrolysis(b), separation (c), saponification (d), esterification (f) anddistillation (g). It is most desirable, as illustrated with respect tothe process of FIG. 2, to recycle said recovered alcohol portion to theesterification step (f), the remainder of the recovered alcohol isrecycled to the alkoxylation step (k). A better result is obtainable byrecycling the forerun (n) to the esterification step and the otherfractions (o), if necessary after drying, to the alkoxylation step. (k).

In accordance with the process of FIG. 3, an alkylene oxide adduct ofalcohol having uniform good quality is continuously produced from ahydrocarbon as described above without the need of careful adjustment ofthe alkoxylation and distillation conditions. In the process of FIG. 3there is obtained alkylene oxide adducts which are further improved incolor and odor when compared with those of the process of FIG. 2.Example IV is a specific example of the process.

EXAMPLE I

A straight chain saturated alcohol mixture of an average molecularweight of 200 consisting of C₁₂ - C₁₄ alcohols and containing 2% byweight of impurities consisting essentially of ketones and hydrocarbonswas used as a raw material. 100 kg of the alcohols and 300 g of borontrifluoride etherate were charged to a jacketed stainless steel reactionvessel equipped with a stirrer, a thermometer and an inlet pipe forliquid. The reaction vessel was then purged of air with gaseous nitrogenand its inner pressure was raised to 5 kg/cm² G. Through the liquidinlet there was introduced 38 kg of ethylene oxide into the reactionvessel over about 3 hours as to maintain a reaction temperature notexceeding 70°C, with stirring. The stirring was continued for additional30 minutes. The reaction mixture was then neutralized with a methanolicsodium hydroxide solution, methanol and a trace of ether were distilledoff and precipitated salts were removed by filteration. The reactionmixture was then distilled under reduced pressure until 50 kg ofdistillate was recovered to obtain as residue 88 kg of an adduct of anaverage added mole member (n) of ethylene oxide per mole of alcohol of3.0.

5 kg of the distillate was added with 550 g of orthoboric acid, chargedin a stirred second reaction vessel and stirred at 150°C whiledistilling off liberated water at 300 Torr to effect esterification. Theesterified mixture was then distilled at 190°C, 5 Torr, to distill offabout 200 g of volatile matter, which was discarded. The residue was,after cooling, added to 5 liters of water and agitated at 90°C. Themixture was then allowed to stand still and a layer of aqueous boricacid solution was separated. This procedure was repeated 3 times tocompletely eliminate boric acid from the residue. The oily layer thusobtained was combined with the balance of the distillate and, afterbeing dried under reduced pressure, recycled for esterification of thesecond round of operation. The operation was repeated over and overunder the same operating conditions except that after the second round(1) the purity of recovered alcohol was determined by the followingmanner: purity of recovered alcohol (wt. %) = 100 - (impurity wt. % +combined E O wt. %) where impurity wt. % = carbonyl compounds wt. % +hydrocarbons wt. % combined E O wt. % = weight % of chemically bondedethylene oxide unit based on the weight of recovered alcohol.

The fresh alcohol was charged together with the recovered alcohol intothe first reaction vessel in a total amount as to provide 98 kg of purealcohol constituent, (2) ethylene oxide was fed in an amount, togetherwith the combined ethylene oxide in the recovered alcohol to berecycled, of 38 kg, (3) the quantity of the distillate drawn out of thefirst distillation stage was adjusted to (48 kg + α) wherein α is thetotal weight of impurities introduced into the first reaction vessel,and (4) at all times the amount of a portion of the distillateintroduced into the second reaction vessel was 10 % by weight of thetotal amount of the distillate.

                  Table I                                                         ______________________________________                                        Round Number                                                                             1     3     5   7   10  20  30  50    90                           ______________________________________                                         α(kg)                                                                             2.0   3.5   4.8 5.7 6.9 8.3 8.5 8.6   8.5                           n         3.0   3.0   2.9 3.0 2.9 3.1 3.0 3.0   3.0                          Product                                                                        CV*       0.3   0.3   0.4 0.3 0.3 0.3 0.2 0.3   0.4                          ______________________________________                                         *CV : carbonyl value (in all the tables in this specification)           

As indicated by the results summarized in the above Table I, there wasobtained, on and after 20th round, an alcohol ethoxylate withoutsubstantial change in the quantity of alcohol charged into the firstreaction vessel and the quantity of distillate, in the distillation stepwhile it was necessary to adjust slightly the quantity of alcoholcharged in the early rounds.

COMPARATIVE EXAMPLE I

An adduct of n = 3 was obtained from the same raw alcohols as in ExampleI in the same process as in Example I except that the distillate, i.e.the recovered alcohol, was, after drying, directly recycled to thealkoxylation.

                  Table II                                                        ______________________________________                                        Round Number                                                                            1     3     5   7   10   20  30  50    90                           ______________________________________                                         α (kg)                                                                           2.0   4.0   5.9 7.8 10.7 18  26  45    75                            n        3.0   2.9   2.9 3.1 3.0  3.1 2.9 3.0   3.1                          Product                                                                        CV*      0.3   0.2   0.3 0.4 0.4  0.6 0.8 2.8   6.0                          ______________________________________                                    

As indicated by the above Table II, it was necessary to adjust thequantity of alcohol charged to the first reaction vessel over a fairlywide range. Nevertheless there was not obtained a product of uniformquality as indicated by the fact that the content of impurities in therecovered alcohol did not level off and instead showed a tendency toincrease infinitely and that the carbonyl value also increasedgradually.

EXAMPLE II

The same alcohol as used in Example 1 was ethoxylated in the sameprocedure as in Example 1 and, after removal of the catalyst, subjectedto distillation under reduced pressure to obtain 2 kg of forerun and 48kg of following distillate and, as residue, 88 kg of an adduct of n =3.0. 2 kg of the forerun was charged into a small reaction vessel,admixed with 200 g of orthoboric acid, stirred at 150°C, 300 Torr, whiledistilling off water to effect esterification, and, after being posttreated in the same manner as in Example I, combined with 48 kg of thefollowing fraction, dried under reduced pressure and recycled for thesecond round operation. The operation was carried repeatedly and afterthe second round, in a similar manner as in Example I except that, atall times, 2 kg of forerun was cut away and subjected to esterificationwith boric acid.

                  Table III                                                       ______________________________________                                        Round Number                                                                             1     3     5   7   10  20  30  50    90                           ______________________________________                                         α (kg)                                                                            2.0   2.6   3.1 3.6 4.2 4.6 4.8 4.8   4.8                           n         3.0   2.8   3.0 3.0 3.0 3.1 3.0 2.9   3.0                          Product                                                                        CV        0.2   0.3   0.3 0.2 0.3 0.3 0.2 0.3   0.2                          ______________________________________                                    

As shown in the above Table III, an alcohol ethoxylate of uniform goodquality was obtained by slightly adjusting the charge of alcohols intothe ethoxylation vessel and, in operation during and after the 20thround, without substantial change in the amount of charge into the firstreaction vessel and the quantity of distillate.

EXAMPLE III

Using as a raw material a n-paraffin mixture of an average molecularweight of 184 having 12 to 14 carbon atoms per molecule, a processconsisting of a series of steps (a) to (g), as illustrated in FIG. 2,was operated for 50 days in a completely continuous manner. In oxidationstep (a) there was fed fresh n-paraffin and recovered n-paraffin at atotal feed rate of 25 kg/h together with metaboric acid at a feed rateof 0.6 kg/h and oxidation with air diluted with gaseous nitrogen in theoxidation zone was carried out under the following operating conditions:residence time of 2 hours, reaction temperature of about 170°C, undernormal pressure, and at conversion of n-paraffin of an average 15 %. Inesterification step (b), esterification was carried out under thefollowing conditions: residence time of 30 minutes and reactiontemperature of about 170°C, while charging the forerun from distillationstep (j) of recovered alcohol at a rate of 154 g/h. In distillation step(c), distillation was carried out under a pressure of 5 Torr to obtainan effluent from the bottom of the kettle at a rate of about 4 kg/h. Insaponification step (d), the distillate was stirred with an amount of 20% by weight, based on the weight of the oily layer in the distillate, ofa 10 % aqueous sodium hydroxide at 100°C for a residence time of 1 hourand then recycled to oxidation step (a), after being washed with water.In hydrolysis step (e) and separation step (f), the bottom liquid fromdistillation step (c) was contacted countercurrently with a mixture offresh water and a boric acid-containing mother liquor from the boroncompound recovery step, the mixture being fed at a total rate of about 4liter/hr under the following conditions: residence time of about 30minutes, temperature of 95°C. An aqueous layer containing boric acid wasfed to the boron compound recovery step, boric acid recovered thereinwas dehydrated into metaboric acid and recycled to oxidation step (a),and the mother liquor was recycled to hydrolysis step (e). Inpurification step (g), a 20 % aqueous sodium hydroxide was supplied at afeed rate to provide 10 % excess alkali over the necessary amount ofalkali calculated on the basis of the saponification value of the crudealcohol and saponification was carried out with stirring at 100°C for aresidence time of about 1 hour. The mixture was then contactedcountercurrently with a stream of water at a feed rate of 4 liter/hr fora residence time of 20 minutes. Distillation of alcohol was then carriedout in a batchwise operation and there was obtained, after removal ofwater and forerun, purified alcohol at a rate in average of 2.9 kg/hr.Crude alcohol obtained in continuous operation for 24 hours wasdistilled in one batch, and the distillation was carried out under apressure of Torr to recover the fraction boiling in the range of from130° to 180°C as the purified alcohol. The alcohol thus obtained was fedto ethoxylation step (h) together with the remaining fractions ofrecovered alcohol from distillation step (j). Step (h) to step (j) werecarried out, for convenience, in a batchwise operation and there wasrepeated ethoxylation of about 140 kg/batch of alcohol. Accordingly, thealcohol from step (a) to step (g) was consumed in operation, one batch aday. In ethoxylation step (h), there were charged 69.5 ± 0.5 kg/batch offresh alcohol and 70 ± 0.5 kg/batch of recovered alcohol, 400 g/batch ofboron trifluoride etherate and 44.4 kg/batch of ethylene oxide. Theethoxylation and catalyst removal in step (i) were carried out insimilar ways as in the corresponding steps in the process of Example I.In step (j), distillation was carried out under a pressure of 5 Torr toobtain 3.7 kg/batch of a forerun and (70 ± 0.5) kg/batch of thefollowing fraction and, as residue, an average 110 kg/batch of analcohol ethoxylate of n of closely 3. The forerun was recycledcontinuously at a rate of 154 g/hr to esterification step (b), and thebalance of recovered alcohol was, after drying, recycled to step (h).The value of n and of C.V of the product after 10 days operation were3.0 ± 0.1 and 0.2 to 0.4, respectively. The color value of the productwas below A.P.H.A. 100.

EXAMPLE IV

Using the same raw paraffin as used in Example III, each operation ofstep (a) to step (i) in accordance with the process of FIG. 3 wascarried out for 50 days in a continuous manner. Oxidation step (a) wasperformed in the same way as in Example III. In hydrolysis step (b) andseparation step (c), the oxidation mixture from oxidation step (a) wascontacted countercurrently at a residence time of about 30 minutes witha mixture of fresh water and the boric acid-containing mother liquorfrom boron compound recovery step the mixture being fed at a total rateof 10 liter/hr. The aqueous layer containing boric acid in a highconcentration was introduced into the boron compound recovery stage inwhich recovered orthoboric acid was dehydrated into metaboric acid andrecycled to oxidation step while the mother liquor was recycled tohydrolysis step (b). The organic layer from separation step (c) wasstirred in saponification stage (d) at 100°C for a residence time ofabout 1 hour with a 20 % aqueous sodium hydroxide being fed at a rate toprovide 10 % excess alkali over the necessary amount of alkalicalculated on the basis of the saponification value of the organic layerand was then contacted countercurrently for a residence time of 20minutes with a stream of water fed at a rate of 10 liters/hr. Inesterification step (e), the effluent from state (d) was treated,together with the recycle from distillation step (m), at a temperatureof 150°C under reduced pressure for a residence time of 1 hour withorthoboric acid fed at a rate of 600 g/hr, with the elimination ofliberated water. In distillation step (f), the effluent from step (e)was processed in the same way as in the distillation step (c) in ExampleIII. The distillate thus obtained was recycled directly to oxidationstep (a). The residue was processed in hydrolysis step (h) andseparation step (i) in the same way as in steps (e) and (f) in ExampleIII, an aqueous layer containing a large amount of boric acid thusseparated was introduced into the boric acid recovery step in whichorthoboric acid was recovered. The orthoboric acid recovered wasrecycled to esterification step (e) and the mother liquor was recycledto hydrolysis step (b). The organic layer separated in separation step(i) was processed in distillation step (j) in the same way as in thedistillation step (g) in Example III to obtain as distillate an alcoholat a rate in average of 2.9 kg/hr. Each operation in steps (k) to (m)was carried out in the same way as in steps (h) to (j) in Example III,while recycling the forerun of recovered alcohol at a rate of 154 g/hrto esterification step (e). The ethoxylate thus obtained was of similarquality with that of the product of Example III except for its colorbelow of APHA 50.

What is claimed is:
 1. In a method of manufacturing alkylene oxideadducts of an aliphatic alcohol which comprises the steps of:a. admixingan alkylene oxide having 2 to 4 carbon atoms with the aliphatic alcoholin the presence of an acid catalyst selected from the group consistingof sulfuric acid, phosphoric acid and Friedel-Crafts catalysts to forman addition reaction mixture and b. distilling said reaction mixture toobtain an alcoholic distillate and a residue consisting essentially ofan alkylene oxide adduct of the aliphatic alcohol;wherein said aliphaticalcohol is obtained by the liquid phase oxidation of a saturatedaliphatic hydrocarbon having 8 to 20 carbon atoms in the presence of aboron compound by contacting with a molecular oxygen containing gas; theimprovement comprising: i. combining said method of manufacturingalkylene oxide adducts with a method of manufacturing the aliphaticalcohol employed in step (a) which method comprises the steps of:a'.subjecting a saturated aliphatic hydrocarbon having 8 to 20 carbon atomsto oxidation by contacting said hydrocarbon with a molecularoxygen-containing gas in the liquid phase in the presence of a boroncompound which is capable of forming a boric acid upon contact withwater to form a reaction mixture containing a borate ester, b'.contacting said reaction mixture with water at a temperature between 20°and 200°C to form an organic layer and an aqueous layer, the weightratio of water to said reaction mixture being between 10:1 to 1:10, c'.separating said layers, d'. subjecting said organic layer tosaponification by contacting said organic layer with an aqueous alkalimetal hydroxide, e'. adding a compound selected from the groupconsisting of orthoboric acid, metaboric acid, pyroboric acid and boricacid anhydride to the saponified organic layer to convert the alcohol insaid organic layer into the corresponding borate ester, f'. distillingthe resulting mixture of step (e') to obtain a crude borate esterresidue and a distillate consisting essentially of unreacted hydrocarbonand volatile by-product, g'. recycling said distillate to oxidation step(a'), h'. contacting said residue with water at a temperature between20° to 200°C to form a second organic layer and a second aqueous layer,the weight ratio of water to said residue being between 10:1 to 1:10,i'. separating said layers, and j'. distilling said second organic layerto obtain a product consisting essentially of said aliphatic alcohol;and ii. cycling 1 to 50% by weight of the distillate from step (b) ofthe method of manufacturing the alkylene oxide adducts to any of thesteps (b'), (c'), (d'), (e') or (f') of the method of manufacturing thealiphatic alcohol.
 2. A method according to claim 1, wherein the averagenumber of adduct moles of said alkylene oxide per aliphatic alcohol isbetween 1 and
 6. 3. A method according to claim 1, wherein said acidcatalyst is selected from the group consisting of boron trifluoride andboron trifluoride complexes.
 4. A method according to claim 1, whereinsaid compound of step (e') is employed in an amount of 0.3 to 3gram-atoms of boron atom per mole of alcohol.
 5. A method according toclaim 1, wherein said saturated aliphatic hydrocarbon in step (a') is atleast one member selected from the group consisting of n-decane,n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane,n-hexadecane, n-heptadecane and n-octadecane.
 6. A method according toclaim 1, wherein 1 to 50 % by weight of said distillate from step (b) isrecycled to the step (e').
 7. A method according to claim 1, whereinsaid alkylene oxide is ethylene oxide.
 8. A method according to claim 1,wherein said boron compound in step (a') is selected from the groupconsisting of boric acids, salts of boric acids, boric acid anhydride,borate esters and boroxines.